What is a cancer of the esophagus?
A cancer of the esophagus can be an abnormally dysregulated proliferative cell in the esophagus – the muscular tube which connects the throat with the stomach. Esophageal cancers generally arise from the cells that make up the lining surrounding the esophagus or the muscles surrounding the tissue.
Esophageal tumors could be benign or cancerous. Malignant tumors are invading and are more likely to metastasize (spread across other parts in your body). The majority of tumors in the esophagus are malignant.
Esophageal tumors are uncommon in both cats and dogs. The most frequent types of esophageal tumors comprise Squamous Cell Cancers (cats) and leiomyosarcomas (dogs) as well as fibrosarcomas osteosarcomas and undifferentiated sarcomas All of them are malignant. There are benign tumors that can occur including leiomyomas (the most commonly encountered) as well as plasmacytomas. Esophageal tumors typically occur on the upper portion of the stomach of cats, and for dogs, the majority of them are located in the lower part of the esophagus.
“Esophageal tumors are very uncommon in cats and dogs. “
What is the cause of this cancer?
The reason a specific pet might develop this, or any other type of tumor isn’t clear. A small percentage of cancers and tumors have a specific reason. They are usually caused by a mix of risk factors, including some related to the environment and some that are inheritable or genetic.
In dogs, the majority of cases of esophageal osteosarcoma and fibrosarcoma and undifferentiated Sarcoma are a result of the spirocercosis. Spirocercosis is an infection that is caused by Spirocerca Lupi which is a form of roundworm that is found in subtropical and tropical regions like the south-eastern USA. When each S. Lupi worm gets settled within the esophagus’s wall the esophagus, it triggers an inflammation nodule to grow around it. The inflammatory nodules could eventually transform into malignant tumors and eventually become esophageal Sarcoma. Apart from spirocercosis, there is no cause for esophageal cancers.
What are the warning signs of esophageal cancer?
The symptoms of esophageal cancers can be different and directly linked to the dimensions of cancer. As the tumor expands in size, it is progressively affecting or blocks the flow through the throat of foods into the stomach. The signs typically show up gradually and often are not noticed until the cancer is advanced.
It is possible that your pet is having more difficulties, or pain when swallowing, or begins to make drool. There could be instances of coughing or choking when eating. It is also possible to notice the appearance of vomiting but is really regurgitation (i.e. emptying from the stomach and not the stomach). In time, as your pet’s capacity to eat and overall health declines and you notice the pet’s weight is dropping and may cease eating completely. When you have difficulty swallowing, choking episodes or frequent regurgitation there’s a significant possibility of suffering from aspiration pneumonia. A sign of pneumonia is symptoms of coughing, fever, and discharge from the nose.
How can this cancer be diagnosed?
The diagnosis of this cancer is usually made through various imaging techniques as well as an endoscopic surgical or biopsy. The chest radiographs (X-rays) might reveal that there is a dilated esophagus (megaesophagus) or an esophageal tumor. If the X-rays show fluid, air or food within an esophagus that is distended or a mass your doctor may suggest more sophisticated imaging to determine how the esophagus functions (e.g. fluoroscopy, or a real-time X-ray film) or to better identify the root of the issue (e.g. positive contrast radiography like barium, computed tomography or magnetic resonance imaging). Chest X-rays could also reveal signs for the presence of metastasis (spread) towards the lung and aspiration pneumonia.
“A final diagnosis of cancer in the esophagus could be determined through endoscopy or biopsy.”
An accurate diagnosis of cancer in the esophagus can be established through endoscopy and biopsy. Endoscopy utilizes an instrument called the endoscope (i.e. it is a slim tube with a bright small camera and a light at the bottom, and through which forceps are used to collect tissues samples). The biopsies are later sent to a pathologist who will examine them under a microscope, and to identify the kind of cancer. This is known as histopathology. Histopathology isn’t just helpful in determining a diagnosis, but it can also reveal how the tumor may behave. Surgery to remove the tumor could be suggested if an endoscopic examination is not conclusive. This will be discussed in the following. If it is benign the procedure may be beneficial. Occasionally, S. Lupi roundworm eggs can be found in the feces and stools of dogs with Esophageal Sarcomas.
What is the typical way that cancers advance?
The majority of malignant tumors are locally infiltrating and can spread to lymph nodes that surround them or different parts of the human body. Spirocerca-induced esophageal tumors tend to metastasize often to the lung. Because there is a chance of metastasis screening (searching for the possibility of spread to other parts of your body) is strongly advised. This can include urinalysis, bloodwork or X-rays taken of the lungs and perhaps an abdominal ultrasound. If lymph nodes appear expanding or abnormal, further samples could be conducted to determine if there is any spread there.
Another possible complication associated with Spirocerca-induced esophageal tumors is a rare condition known as hypertrophic osteopathy. Hypertrophic osteopathy is that is characterized by pain-inducing ankle swelling and lameness and the feeling of being tired. It is seen in dogs suffering from particular types of infections as well as cancers.
What are the options for treating these types of tumors?
Treating malignant cancers is difficult to say the least because typically, they are detected in advanced stages that is, they’ve already been resected or have grown too large for them to cause complications because of tension in the area of surgery. Treatment for the upper part of the esophagus (the neck-throat region) could be feasible, but not for the lower or middle esophagus (the chest region). It is generally not beneficial in malignant tumors. Chemotherapy has not demonstrated the greatest benefit, unfortunately.
benign tumors, like leiomyomas, can be surgically removed through surgical removal. Before they become cancerous, the condition can be treated with medicines such as doramectin and moxidectin as well as milbemycin.
Do you have any other information I need to be aware of?
Surgery for the esophagus can be challenging and can lead to complications. A benign tumor can be removed and have a favorable prognosis, however in the majority of instances, the prognosis for Esophageal tumors is not very good. Sometimes, palliative treatment may be an option through the use of a gastrotomy tube feeding system (placed right into your stomach) that is usually tolerated by pets and are kept for a period of weeks or months with proper care.